Dextrofenfluramine and its pharmaceutically-acceptable acid addition salts thereof are by now well known in the art. It is entry 3920 on page 624 of The Merck Index, Eleventh Edition, and the subject matter of French Patent M1658, U.S. Pat. Nos. 3,198,833, and 3,198,834 by Beregi et al. U.S. Pat. No. 4,309,445 by Wurtman and Wurtman discloses that dextrofenfluramine may be administered to patients having a syndrome of abnormal need for carbohydrate in order to reduce this need without inhibiting the consumption of proteins in their diet at a dosage of 10 to 60 mg per day.
U.S. Pat. No. 4,649,161 of Wurtman discloses a method for the treatment of depression using dextrofenfluramine at a dosage of 2.5. to 120 per day.
Hitzig U.S. Pat. No. 5,502,080 discloses the combined use of dopamine and serotonin agonists in the treatment of allergic disorders and treats this disorder of the immune system by administering a combination of 10 to 90 mg of fenfluramine and 15 to 500 mg of phentermine to the patient per day in single or divided doses, preferably 10 to 90 mg of fenfluramine and 15 to 160 mg of phentermine per day in single or divided doses. This patent discloses the use of fenfluramine for the treatment of immunodeficiency states such as AIDS and HIV- related diseases, and it states that patients with AIDS experience significant improvement of their T-cell counts. In addition, it states that the amount of fenfluramine administered is 10 to 120 mg/day, preferably 80 mg/day, in single or preferably divided doses of 40 mg each, and that it may be in the form of either optical isomer or a racemic mixture thereof. In the present case, it is to be noted, only dextrofenfluramine is employed.
Finally, French Patent FR 2663539, filed Jun. 22, 1990, published Dec. 27, 1991, and granted Oct. 7, 1994 discloses the employment of dextrofenfluramine or an acid addition salt thereof in a pharmaceutical composition for the production of medicinal products for the treatment of diseases due to immune deficiencies in elderly subjects at a dosage ranging from 1 mg to 15 mg per dose or per application. Such studies indicate that their results are age and sex dependent.
The method of the present invention, in contrast, is clearly not age or sex dependent in humans, and employs only about 1 to about 9 mg of dextrofenfluramine or salt thereof per day and preferably about 4.5 mg of dextrofenfluramine or salt thereof per dose, with the preferred daily dosage being between about 1 mg and 9 mg, whether to any human patient for the stimulation or enhancement of lymphocyte activity against tumors or for the treatment of immunocompromised humans, representatively those immunocompromised by AIDS or HIV positive infection, the administration of dextrofenfluramine or a pharmaceutically-acceptable acid addition salt thereof to such a patient being of a lymphocyte-activity-enhancing amount which, as will be noted, differs considerably from the type of subject previously treated, the indication being treated, and the dosage regimen involved.
In addition, previously published work by one of the inventors and others in healthy, normal animals does not in the slightest suggest that enhancement of lymphocyte activity could be effected in immunocompromised humans.